My friend and I have 3 mini's, 1 Shetland pony and 4 full size horses plus a wide variety of chickens, 2 ducks and 2 turkeys. They are all at my friends house and she has well water. Since it's been hot, we have noticed a lot of algae forming in their troughs and watering dishes. I have done some reading on using apple cider vinegar for algae control in the troughs but they don't mention the ratio of the vinegar per gallon of water. Does any one know the ration of vinegar per gallon of water to use for the troughs for algae control? I don't want to put too much in there to where the horses won't drink the water or get sick from too much but enough to control the algae. I've read that the vinegar is beneficial for the digestion and provides a shine on the horses coats plus is also a good fly spray, which we have an overabundance of. Would the vinegar be okay for the poultry? Their water dishes and the small duck pool get full of algae too and it's a pain in the butt to have to scrub them on a constant basis along with the horse troughs. We do give them fresh water every day but the algae just keeps on growing making it hard to keep the water fresh for all of the animals. The smaller dishes of water are dumped out every day, cleaned, and filled with fresh water and the big horse troughs are completely dumped of water, cleaned, and filled with fresh water once a week. Any suggestions on natural algae control would be great [please don't suggest inorganic chemicals]. Thanks.